Tooth for digging equipment used in caliche and similar strata



June 9, 1964 w. M. TROEPPL. 3,136,077

TOOTH FOR DIGGING EQUIPMENT USED IN CALICHE AND SIMILAR STRATA Filed June 19, 1962 INVENTOR. WlL L/AM M. T/EOEPPL ATTORNEY United States Patent Giff 3,136,077 Patented June 9, 1964 TOOTH FOR DIGGING EQUIPMENT USED IN CALICHE AND SIMILAR STRATA William M. Troeppl, Santa Clara, Calif., assignor, by

direct and mesne assignments, of one-half to Gerald A. Petersen, Santa Clara, Calif and one-half to Anita E. Petersen, Saratoga, Calif.

Filed June 19, 1962, Ser. No. 203,492

2 Claims. (Cl. 37-142) This invention relates to a new and improved tooth for digging equipment used in caliche and similar strata. More particularly the inventon relates to the structure of a tooth used in earth digging tools such as earth augers, trenching machines and a wide variety of other digging tools. Reference is made to US. Patents Nos. 2,877,574, 2,952,085 and 2,968,880 on which the present invention is an improvement.

In the aforementioned patents, means are shown for securing an earth digging tooth to a shank plate attached to digging equipment or directly to the digging equipment itself. Similar means may be used to attach the tooth hereinafter described in detail to such equipment. The present invention is directed to a tooth having a particular shape of the distal portion which adapts the tooth to digging in caliche, hardpan, sandstone and rock or similar strata under severe operating conditions. The bottom of the tooth slices into the compacted soil and the top surface fractures the soil sliced by the bottom. The shape of the distal portion of the tooth cooperates with the shape of the proximal portion thereof to insure effective retention of the tooth in its shank plate or other holder.

The shape of the distal portion of the tooth is such that the hard and brittle soil or rock structure is broken away in an explosive action by reason of the tapered shape of the tooth and central ridge or spine on the top and the angularly disposed and curved top surfaces hereinafter described. Accordingly, the tooth may be used to dig through strata not heretofore capable 'of excavation by equipment of the type heretofore described.

A particular use for the invention is in excavation for holes for telephone and other utility poles and in digging of trenches for cables as commonly used in the utility industries. The present invention enables the equipment conventionally used in dirt and clay soils to be used in areas such as Arizona, Las Vegas, Nevada, San Diego and East Sacramento, California, where a hard structure known as caliche, hard pan, sandstone and rock are encountered and where heretofore the teeth on such equipment have failed to perform satisfactorily. Other soil strata which are highly compacted can be excavated.

Essentially the action of the tooth is a penetration of the soil and a rapid and violent movement of the dirt away from the tooth. This action has been referred to above as explosive as contrasted with the less violent, shearing action of conventional teeth in digging clay and dirt.

Other objects of the present invention will become apparent upon reading the following specification and referring to the accompanying drawings in which similar characters of reference represent corresponding parts in each of the several views.

In the drawings:

FIG. 1 is a perspective view of a tooth in accordance with the present invention.

FIG. 2 is a top plan thereof.

FIG. 3 is a side elevation.

FIG. 4 is a rear elevation.

FIG. 5 is a fragmentary, horizontal sectional view taken substantially along the line 5-5 of FIG. 6 showing a portion of the tooth in accordance with this invention held in a shank plate or holder in a manner similar to the holding means shown in Patent No. 2,968,880.

FIG. 6 is a sectional view taken substantially along the line 6-6 of FIG. 5.

FIG. 7 is a View similar to FIG. 6 showing a different means for securing the tooth in its holder in accordance with the means shown in Patent No. 2,952,085.

The proximal portion of the tooth shown in FIGS. 1 to 4 inclusive is essentially the same as that shown in the Petersen Patents Nos. 2,877,574, 2,952,085 and 2,968,880 heretofore mentioned. Proximal prongs or roots 16 on either side of the tooth are separated from each other by a slot 17 having vertical walls 18 which extend forwardly from the proximal ends 20 of the tooth. At the forward end of slot 17 is a rectangular extension 19 having vertical front and side walls 21, 22, 22. Each prong 11 has a top and a bottom surface 23, 24 which is preferably flat and which are preferably parallel to each other but which may be slanted if desired. Vertical side walls 18 define the sides of slot 17 and vertical outside edges 26 define the outside of the prongs, edges 18, 22 and 26 being parallel to each other and to the length of the tooth. Transverse notches 27 are formed on the top and bottom surfaces 23, 24 of each prong in the form of the invention shown in FIGS. 1-4 and 7. The retaining means holding the tooth in its holder in FIG. 6 is a resilient insert 31, as best shown in Patent No. 2,968,880. Use of insert 31 makes presence of notches 27 optional so that they may be eliminated if desired.

In FIGS. 5 and 6 the holder or shank plate 32, which may be secured in various Ways to a variety of digging equipment, is essentially H-shaped in the sense that it is formed with a vertical web 33 which extends between spaced upper and lower transverse flanges 34, 36. The cross-sectional shape of web 33 is such as to fit inside slot 17 with a slight clearance between the edges of the web and the side walls 18 of the slot. The top and bottom walls 37, 38 of the H-shaped opening engage the top and bottom surfaces 23, 24 of the prongs of the tooth. Extending transverse horizontally through web 33 is a hole 39 which receives resilient insert 31 formed of rubber, neoprene or the like which is preferably circular incross-section. The length of insert 31 is substantially greater than the width of web 33. In order to allow. insert 31 to bend backwardly, grooves 41 are formed in the walls of web 33 rearwardly of hole 39, said grooves 41 preferably being semi-circular in cross-section. Grooves 41 enable the insert 31 to bend backwardly as shown in FIGS. 5 and 6 when the tooth is driven in position. Thus, in installing the tooth, prongs 16 are inserted in the openings to either side of web 33 and the proximal ends of the tooth bend insert 31 back to assume the position shown in FIGS. 5 and 6. Insert 31 bears against walls 18 of the tooth and causes the shank plate 32 to grip the tooth so that it cannot be readily dislodged. Normal usage of the earth digging equipment will not cause dislodgrnent of the tooth. By reason of the resilient nature of insert 31, wear, vibration, the abrasive action of sand, gravel or rocks in which the tool is digging, and the like, will not ordinarily cause separation of the tooth from the shank plate.

In the form of the invention shown in FIG. 7, the shank plate 32a or holder is formed with a step at its forward end the back wall 46 of which abuts ends 20 of prongs 16. The tread 47 of the step has'upward projections 48 which are complementary to, and nest in notches 27 on the bottom surfaces 24 of each prong 16. At the center of the front of tread 47 is an upward projection 49 which fits into extension 19 of slot 17. A hole 51 is formed in plate 32a immediately rearwardly of upward projection 49 and forwardly of projections 48. A bolt 52, such as a carriage bolt, fits through hole 51. The enlarged head 53 of bolt 52 rests upon the top surfaces 24 of the two snugly in the forward end of slot 17. Nut 57 on shank 54 secured bolt 52 in position. Projections 48 in notches 47 prevent forward dislodgment of the tooth so long as bolt 52 is tightened. Projection 49 and the complementary shape of the step and tooth hold the tooth rigidly secure relative to holder 32.

As previously stated, the distal portion of the tooth differs from that shown in the patents heretofore mentioned. Thus, the disatl side edges 61 of the tooth are essentially vertical and in plan view etxend forwardly in an ogee curve. At the forward ends of curved edge 61 the curve is so flat that at reference numeral 62 it is substantially parallel to side edges 26 of the proximal portion. At the front end the width between edges 62 is only about one-third the distance between edges 26. The front end 63 of the tooth viewed in plan is vertical and transverse to edges 62. Extending down the center of the top of the tooth is spine 66. Spine 66 slopes up from the forward end of extension 19 at about a 45 angle to a peak 67 about one-fourth the distance forward of the proximal end of the tooth and then slopes downwardly-forwardly at a 30 angle toward the front end. The thickness of the tooth at peak 67 is about twice that at the prongs and at the front end 63 about one-half that at prongs 16. The corner 68 between the front end of spine 66 and end 63 is bevelled in a triangular surface 68. The flanks 69 of the spine are curved in arcuate surfaces of relatively large radius. Rearwardly of spine 66 surfaces 71 of the tooth are blended to smoothly fill out the transition from the flat top surfaces 23 of prongs 16 to peak 67.

The bottom surface of the distal portion is almost fiat, but has a slight concavity of maximum extent indicated by reference numeral 72. This shape augments penetration of the soil.

In use in an earth anger, the end 63 of the tooth penetrates the stratum and the spine 66 rather violently fragments the caliche or other brittle, highly compacted dirt in a manner resembling an explosion. Such action is particularly effective in digging holes by means of an earth auger, such as that shown in Petersen Patent No. 2,578,- 014.

In using the tooth in the trenching machine, the two curved flanks 69 cooperate to cut into the stratum and the narrow front end 63 of the tooth penetrates into the rock or soil.

In the form of tooth shown in FIGS. 1 to 4 and 7,

notches 27are formed in the top and bottom surfaces of each prong to cooperate with projections 48, shown in FIG. 7, to assist in holding the tooth in place in shank plate 32a. In the form of tooth shown in FIGS. 5 and 6, no notches are shown since a different means of attachment is used. The extension 19 is also eliminated in this form of the tooth.

Although the foregoing invention has been described in some detail, by way of illustration and example for purposes of clarity of understanding it is understood that certain changes and modifications may be practiced within the spirit of the invention and scope of the appended claims.

What is claimed is:

1. A replaceable earth digging tooth for penetration and explosive-like excavation of brittle, compacted soils having a proximal portion formed with cooperative means for attaching said proximal portion to earth digging equipment and a distal portion, said proximal portion formed with its lowermost points lying substantially in a common bottom plane, said proximal portion having substantially parallel side edges, said distal portion being substantially more narrow in plan than said proximal portion, the top surface of said distal portion formed with a substantially straight longitudinally extending spine sloping downwardly-forwardly, the flanks of said top surface of said distal portion on either side of said spine being concave, the front end of said tooth being truncated and square, the side edges of said distal portion being substantially vertical and in plan being shaped with forward edges parallel to each other and to said parallel side edges of said proximal portion, and smoothly-inwardly curved edges interconnecting said side edges of said proximal por tion and said side edges of said distal portion, the bottom surface of said tooth being generally fiat for cooperation with said front end for cutting into the soil and lying in said common bottom plane, said flanks shaped to break away soil cut by said end and bottom surfaces.

2. A tooth according to claim 1 in which the bottom of said distal portion is formed slightly concave.

References Cited in the file of this patent UNITED STATES PATENTS 309,553 Manning Dec. 23, 1884 FOREIGN PATENTS 7 428,327 Great Britain May 10, 1955 

1. A REPLACEABLE EARTH DIGGING TOOTH FOR PENETRATION AND EXPLOSIVE-LIKE EXCAVATION OF BRITTLE, COMPACTED SOILS HAVING A PROXIMAL PORTION FORMED WITH COOPERATIVE MEANS FOR ATTACHING SAID PROXIMAL PORTION TO EARTH DIGGING EQUIPMENT AND A DISTAL PORTION, SAID PROXIMAL PORTION FORMED WITH ITS LOWERMOST POINTS LYING SUBSTANTIALLY IN A COMMON BOTTOM PLANE, SAID PROXIMAL PORTION HAVING SUBSTANTIALLY PARALLEL SIDE EDGES, SAID DISTAL PORTION BEING SUBSTANTIALLY MORE NARROW IN PLAN THAN SAID PROXIMAL PORTION, THE TOP SURFACE OF SAID DISTAL PORTION FORMED WITH A SUBSTANTIALLY STRAIGHT LONGITUDINALLY EXTENDING SPINE SLOPING DOWNWARDLY-FORWARDLY, THE FLANKS OF SAID TOP SURFACE OF SAID DISTAL PORTION ON EITHER SIDE OF SAID SPINE BEING CONCAVE, THE FRONT END OF SAID TOOTH BEING TRUNCATED AND SQUARE, THE SIDE EDGES OF SAID DISTAL PORTION BEING SUBSTANTIALLY VERTICAL AND IN PLAN BEING SHAPED WITH FORWARD EDGES PARALLEL TO EACH OTHER AND TO SAID PARALLEL SIDE EDGES OF SAID PROXIMAL PORTION, AND SMOOTHLY-INWARDLY CURVED EDGES INTERCONNECTING SAID SIDE EDGES OF SAID PROXIMAL PORTION AND SAID SIDE EDGES OF SAID DISTAL PORTION, THE BOTTOM SURFACE OF SAID TOOTH BEING GENERALLY FLAT FOR COOPERATION WITH SAID FRONT END FOR CUTTING INTO THE SOIL AND LYING IN SAID COMMON BOTTOM PLANE, SAID FLANKS SHAPED TO BREAK AWAY SOIL CUT BY SAID END AND BOTTOM SURFACES. 